Agglomerates of the above specified type are commonly used in the food, chemical, agrochemical and pharmaceutical industries and have many applications, e.g. fertilizers, liquid absorbents (for industrial environments and ecological purposes), herbicides, insecticides, compost, animal feed, soil mixtures, etc.
However, each application requires an agglomerate having specific qualities, e.g. liquid absorption ability, color, smell, size, shape, taste, weight, hardness, low dust discharge, etc.
Preparing a uniform agglomerate in which each of the above qualities may be controlled, requires first particulating the fibrous material and reducing the size of the other components (mineral material and additives) into small, substantially homogeneous particles, thoroughly mixing, and binding with a suitable binder, forming the agglomerate into the required size and shape and finally, drying.
Several agglomeration processes are known. According to one type of process, all the agglomeration ingredients are comminuted and mixed together with a binding agent in a wet form. Then, the mixture is introduced into a lower end of a long inclined drum, which drum comprises heating means and is rotatable along its longitudinal axis. The mixture agglomerates as it ascends along the rotating drum and as it exits from the top end of the drum, it is dry and ready for use.
Another agglomeration method uses a long, inclined conveyor belt for agglomerating the mixture, with heating means provided along the belt for drying the agglomerate.
Both these processes share several drawbacks. First, when using light fibrous organic materials such as paper or cotton, the agglomerate obtained is non-uniform that, owing to the relatively long agglomerating means. Second, the amount of energy required for these processes is substantially high. particularly since the agglomeration drum or belt are essentially long and heat is applied practically throughout their entire length for drying the agglomerate. Furthermore, the equipment is large and heavy and thus requires large space.
Still furthermore, approximately 15-20% of the agglomerate produced according to the above methods is off-size or out of shape and thus requires reprocessing by first re-comminuting the dry agglomerate and then agglomerating it again as above described, since the agglomerate can not be screened during the process in wet form, i.e. prior to drying.
Also, the high temperatures and relatively prolonged drying period required for drying the agglomerate is not suitable for certain materials, e.g. paper fiber, since they are likely to burn. Qualities of other organic materials may be damaged by the excessive heat.
Moreover, these processes provide less control of the above-mentioned qualities, in particular the important parameters of granules size, specific weight, liquid absorption ability and color.
It is the object of the present invention to provide a novel, essentially uniform aggregate of organic fibers and mineral powdered material, with the above-referred to disadvantages being significantly reduced or overcome. It is a further object of the invention to provide a process for the manufacture of such an agglomerate.